

While I agree, the best practice is one you can do regularly. If duo’s gamification helps you keep actively studying, then while maybe not the best way, it’s better than nothing.
Ideally the best use of duo is minimally, as a springboard to keep you doing other more immersive studying.
Just as a mild counterexample, I’ve personally changed my views quite drastically over my time on reddit and now lemmy, and most of it was from individuals just sharing their own perspective.
I held some latent bigotry and misogyny, part of which I picked in my day to day life, and partly from 4ch. I won’t say I’ve eliminated it completely, but I think I’ve become a better person from my interactions online.
If we’re not out here trying to actively learn from and help other people, then what the heck are we doing?